Heat dissipating device in a fan

ABSTRACT

A heat dissipating device in a fan includes a fan blade assembly with a fan blade hub, a fan base attached to the fan blade assembly and a motor unit attached to the fan base. The fan base has at least a pillow part and is formed with an air opening and a flow passage corresponding to the fan blade hub such that part of fluid driven by the fan can be guided into the fan blade hub to cool the motor unit received therein so as to prolong life span of the entire fan.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention is related to a heat dissipating device in a fanand particularly to a fan in which a support base incorporated with sizeand configuration of a hub such that once the fluid is driven to move, apart of the fluid passes through a heat generation object and anotherpart of the fluid is guided into the hub to cool the motor received inthe hub effectively.

2. Brief Description of Related Art

Referring to FIG. 1, a conventional fan assembly includes a fan frame 11and a hub 12. The fan frame 11 has a support base 111 inside with ahollow axial barrel 112. The axial barrel 112 is attached with a bearing113 inside and a stator 13 outside such that the stator 13 can belocated at the support base 111. The hub 12 is a shield member with aclosed end and an open end with a shield cover 14 inside. The shieldcover 14 has a closed end and an open end too and an annular rotor 15 isattached to the inner side of the shield cover 14. The hub 12 provides aplurality of radial shaped fan blades 121. A spindle 16 connects withthe hub 12 and the shield cover 14 at an end thereof and passes throughthe bearing 113 at another end thereof to allow the hub 12 and theshield cover 14 movably connect with the support base 111. When thestator 13 and the rotor 15 are magnetized, the hub 12 and the shieldcover 14 are driven to rotate with fan blades 121 due to change of phasesuch that fluid moves to cool the heat dissipation object.

However, all the fluid 13 moved by the conventional fan only passesthrough the heat generation object (not shown) but heat can be generatedbetween the stator 13 and the rotor 15 he fan blades 121. Heat exchangerate between the preceding heat and the outside air is low due to theshield cover 14 being completely enclosed in the hub 12 and it resultsin a great deal part of the heat stays in the shield cover 14 not onlyto decrease life span of the fan itself but also to increase heat of theentire system.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a heatdissipating device in a fan with which a support base is incorporatedwith size and configuration of a hub such that once fluid is driven bythe fan to move, a part of the fluid passes through a heat generationobject and another part of the fluid is guided into the hub to cool themotor received in the hub effectively.

Another object of the present invention is to provide a heat dissipatingdevice in a fan with which air current created by the fluid directedinto the fan blade hub can decrease swinging of the fan.

In order to achieve the preceding objects, the heat dissipating devicein a fan according to the present invention includes a fan bladeassembly with a fan blade hub, a fan base attached to the fan bladeassembly and a motor unit attached to the fan base. The fan base has atleast a pillow part and is formed with an air opening and a flow passagecorresponding to the fan blade hub such that part of fluid driven by thefan can be guided into the fan blade hub to cool the motor unit receivedtherein so as to prolong life span of the entire fan.

BRIEF DESCRIPTION OF THE DRAWINGS

The detail structure, the applied principle, the function and theeffectiveness of the present invention can be more fully understood withreference to the following description and accompanying drawings, inwhich:

FIG. 1 is sectional view of a conventional heat dissipation device of afan;

FIG. 2 is a sectional view of a preferred embodiment of a heatdissipating device in a fan according to the present invention;

FIG. 3 is a sectional view of another preferred embodiment of a heatdissipating device in a fan according to the present invention;

FIG. 4 is a top view of FIG. 2;

FIG. 5 is a top view of FIG. 3;

FIG. 6 is another top view of FIG. 3; and

FIG. 7 is a further top view of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 2, a preferred embodiment of a heat dissipating devicein a fan according to the present invention includes a fan bladeassembly 10, a motor unit 20 and a fan base 30. The fan blade assembly10 is composed of a fan blade hub 11, a shaft 12, a motor case 13 and amagnetic strip 15. The shaft 12 is disposed at a shaft seat 111, whichis at central bottom of the fan blade hub 11. The motor case 13 isdisposed at the inner wall surface of the fan blade hub 11 and themagnetic strip 15 is located at the inner wall surface of motor case 15.

The motor unit 20 is attached to the fan blade seat 30 and is composedof an insulation frame 21, silicone steel sheets 22, a circuit board 23and a coil 24. The silicone steel sheets 22 are provided at the outerside of the insulation frame 21 and surround the insulation frame 21with the coil 24. The fan seat 30 has a central hollow axial seat 31 andthe circuit board 23 is disposed between the bottom of the insulationframe 21 and the axial seat 31. The shaft 12 is received in a chamberformed in the axial seat 31 and a bearing 32 is disposed between theshaft 12 and axial seat 31 and fits with the shaft 12 such that theshaft 12 can rotate with being supported by the bearing 32. An oil ringR is provided between the bearing 32 and the fan blade hub 11.

The axial seat 31 has a projection part 311 and an engaging part 312.The shaft 12 has a circular end free from connecting with the fan bladehub 11 and the circular end engages with a retaining ring 14. Theprojection part 311 interferes with the retaining ring 14 to prevent theshaft 12 from moving away the axial seat 31. The fan blade hub 11 atleast has a pillow part 33 such as a pillow part shown in FIG. 2, aplurality of pillow parts shown in FIGS. 3, 5 and 6 and the periphery ofthe fan base 30 being surrounded with pillow part 33 as shown in FIG. 7.The respect pillow part 33 is formed with an air opening 34 and apassage corresponding to the fan blade hub 11 such that part of fluiddriven by the fan can be guided into the fan blade hub 11 to cool amotor received in the fan blade hub 11 can be cooled completely. In thisway, not only life span of the entire fan can extended but also swingingof the fan can decrease due to the fluid flowing toward the fan bladehub 11.

While the invention has been described with referencing to the preferredembodiments thereof, it is to be understood that modifications orvariations may be easily made without departing from the spirit of thisinvention, which is defined by the appended claims.

1. A heat dissipating device in a fan, comprising: a fan blade assembly,providing a fan blade hub; a fan base, being attached to the fan bladeassembly; and a motor unit, being received in the fan base;characterized in that the fan base at least has a pillow part and thepillow part is formed an air opening and a flow passage corresponding tothe fan blade hub such that part of fluid driven by the fan can beguided into the fan blade hub to cool the entire motor unit so as toprolong life span of the entire fan.